I disagree with this statement and I am pretty sure George Saunders would stand with me. I don’t subscribe to the “Those who can, do. Those who can’t, teach” mentality.
What would I rather do, take an online course about personal essay writing from someone who has had a successful blog or take a class in memoir writing with Mary Karr? I’ll take Mary Karr.
I suppose it’s what you want your body of work to be and what you want it to do for you. If someone wants to make $15k a month with a blog and an email list and listicles, go for it. If you want to write the next Lincoln in the Bardo, an online course ain’t gonna get you there.